Drainwater typically flows out of a commercial building by way of a drain pipe. Such a drain pipe typically has a diameter of 3 or more inches. It is sometimes advantageous to treat or to remove heat from the outgoing drainwater on-site, such as in-house. Many water treatment systems (such as acid neutralization, disinfection, solids removal, and heat recovery) are not able to treat the full flow of drainwater with one unit but instead work much better by treating lower flow in several units.
Drainwater systems in which flow is split for the purposes of water treatment are taught in U.S. Pat. No. 6,092,549 to Eriksson entitled “Device in a Waste Disposal System in a Building” which issued on Jul. 25, 2000, as well as in U.S. Pat. No. 6,261,443 to Eriksson entitled “System for Handling Drain Waters of Different Degrees of Contamination” which issued on Jul. 17, 2001. These two patents are primarily concerned with the separation of drainwater having differing degrees of contamination into separate containers for separate treatment, and employ pumps to regulate the flow of drainwater.
Flow-splitting occurs most commonly when a flow of liquid, such as water or waste water, is split from one or more pipes to a plurality of pipes. Flow-splitting from one 4 inch line to multiple 4 inch lines (e.g. 16 lines) is not specifically prevented in the typical published plumbing codes. However, such flow splitting does not meet the intent of the plumbing codes because it results in a slowing down of the drainwater velocity. The reason for this slowing down is that the total drainpipe cross-sectional area increases substantially as the number of drainpipes used in the system is increased due to desired flow-splitting. Such a situation is exemplified in U.S. Pat. No. 3,853,142 to Gorman entitled “Drainage System” which issued on Dec. 10, 1974, and which relates to a drainage system for multi-floor buildings. Fittings for interconnecting drainpipes which are provided in this system have an inner diameter corresponding to that of the pipes in the stack.
U.S. Pat. No. 5,099,874 to Della Cave entitled “Residential Waste Disposal System” and issued on Mar. 31, 1992 relates to a residential waste water disposal system for a building which saves and recycles the grey waste water for lawn and plant irrigation. The system includes three different types of T-fittings used with two passageway waste water pipes, each T-fitting designed to interconnect to axially aligned waste water pipes and having an offset opening to one of the waste water passageways in the fitting. The figures of the '874 patent show a waste water fitting having two parallel but separate passageways within the pipe, each for different types of drainwater. The different types of fittings disclosed communicate with each other by means of interconnecting passageways or where one passageway meets a wall so as to prevent cross contamination of drainwater in that particular path.
Although different cross-sectional areas are used in certain cases in the '874 patent, they are used in order to selectively limit the flow of certain types of drainwater based on their known contents or degree of contamination. The use of different cross-sectional areas does not improve drainwater flow, or the rate of such drainwater flow. Moreover, such a system does not rely solely on gravity to feed the water through the system, but uses applied pressure, such as pumps to regulate the water flow.
It is, therefore, desirable to provide a system for water supply that allows flow splitting with minimal change in drain water velocity. It is further desirable to provide a system for liquid supply, not limited for use with aqueous solutions, that allows flow splitting with minimal change in liquid flow velocity.